To improve care for victims of sexual assault, specialized assault centers have been developed globally, providing medical, psychological and legal care in one place. Our assault center serves a large population in the center of Israel. In 2010, we initiated a program aimed to prevent assaults among minors and to encourage early referral of victims to the center. The goal of the current study was to assess the impact of this program by comparing the characteristics of sexual assaults before and after the program's initiation. We conducted a historic cohort study of all victims of sexual assaults who were treated in our center between October 2000 and November 2017. A comparison was performed between victims treated before and after January 2010 (early vs. late study period), when the prevention program was initiated. The program mainly included lectures in middle and high schools, and workshops for police investigators. Overall, 3941 victims of sexual assault were treated in our center during the study period. Most victims were females (90.5%). Mean age was 23.0±11.0 years. Most victims were single (93.1%), and approximately half knew their perpetrator before the assault. Compared with the early study period, in the late study period we observed a decrease in the rate of minor victims (31.9% vs. 24.7%, respectively, P<.001) and an increase in the rate of victims who arrived to the center within 3days of the assault (P=.001). However, we observed higher rates of multiple-perpetrator assaults (16.7% vs. 21.9%, respectively, P<.001), alcohol use (29.2% vs. 40.1%, respectively, P<.001), and drug use (7.2% vs. 9.0%, respectively, P=.04). Moreover, in the late study period, fewer victims were willing to press charges (79.5% vs. 64.4%, respectively, P<.001). Our prevention program might have contributed to reducing the rate of sexual assaults among minors and shortened the time interval between the assault and victim's arrival to the center. Nonetheless, more efforts should be taken to reduce the involvement of alcohol and drugs in sexual assaults and to encourage victims to press charges.